/**
*      author: Y_Yao
*      created: 2025-02-20 21:52:25
**/

#include<bits/stdc++.h>

#define int LL
using namespace std;
using LL = long long;
const LL LLINF = 1e18;
const int INF = 0x3f3f3f3f;
const int N = 100 + 7;
int n;

void solve()
{
    cin >> n;
    int prev = 0;
    int h;
    int ans = 0;
    for(int i = 1;i <= n;i++)
    {
        cin >> h;
        if(h > prev)
        {
            ans += h - prev;
        }
        prev = h;
    }
    cout << ans << endl;
}

signed main()
{
    ios::sync_with_stdio(false);
    cin.tie(0);

    int t = 1;
    //cin >> t;
    while(t--)
    {
        solve();
    }
    return 0;
}
